This invention generally relates to slider-operated flexible zippers for use in reclosable pouches, bags or other packages. In particular, the invention relates to gusseted reclosable packages having slider-operated zippers.
Reclosable fastener assemblies are useful for sealing thermoplastic pouches or bags. Such fastener assemblies often include a plastic zipper and a slider. Typically, the plastic zippers include a pair of interlockable fastener elements, or profiles, that form a closure. As the slider moves across the profiles, the profiles are opened or closed. The profiles in plastic zippers can take on various configurations, e.g. interlocking rib and groove elements having so-called male and female profiles, interlocking alternating hook-shaped closure members, etc.
Conventional slider-operated zipper assemblies typically comprise a plastic zipper having two interlocking profiles and a slider for opening and closing the zipper. In one type of slider-operated zipper assembly, the slider straddles the zipper and has a separating finger at one end that is inserted between the profiles to force them apart as the slider is moved along the zipper in an opening direction. The other end of the slider is sufficiently narrow to force the profiles into engagement and close the zipper when the slider is moved along the zipper in a closing direction.
Other types of slider-operated zipper assemblies avoid the use of a separating finger. For example, U.S. Pat. No. 5,809,621 discloses a slider-operated zipper assembly wherein one zipper profile has a pair of handles that cooperate with the slider. As the slider is moved in an opening direction, the handles are squeezed together to disengage the profiles. In U.S. Pat. No. 5,442,838, a slider-operated zipper assembly is disclosed wherein the zipper profiles are engaged and disengaged in the course of a xe2x80x9crolling actionxe2x80x9d. This xe2x80x9crolling actionxe2x80x9d is described as being achieved through cooperation between flanges on the profiles and shoulders which project inwardly from the arms of the slider. U.S. Pat. No. 6,047,450 discloses a zipper comprising a pair of mutually interlockable profiled structures. Portions of the two profiled structures form a fulcrum about which the profiled structures may be pivoted out of engagement when lower edges of the bases are forced towards each other
Gusseted bags having plastic zippers are well known in the reclosable packaging art. One advantage of such gusseted bags is that they may be opened more fully to facilitate filling the bag and later removing its contents. In some designs a gusseted side of the bag can be used to form a pouring spout by pulling the gusset outward and then inverting the bag, in which event the pourable contents of the package can be made to pour down the v-shaped channel formed by the gusset panels.
In early concepts for such bags, the profiles of the plastic zipper had to be sufficiently large to capture a double thickness of the bag film in order to accommodate the gussets when the package was closed. Later designs for gusseted bags have side gussets that include portions aligned with the interlocking zipper profiles that are relatively thin as compared with the remainder of the bag walls.
U.S. Pat. No. 6,325,543 discloses a gusseted bag in which zipper profiles on a carrier strip are attached inside the bag. Profile-free sections of the carrier strip form part of the gusseted sides in the region of the bag mouth. The gussets may be open at both ends of the bag to provide a spout at either end or may be sealed together at one end to provide a spout at the opposite end. The front and rear walls of the bag and the gussets are joined together by interlocking the profiles as well as by capturing the profile-free areas of the gussets between the interlocking profiles. U.S. Pat. No. 6,325,543 does not disclose operating the zipper by means of a slider.
U.S. Pat. No. 6,186,663 discloses an embodiment of a gusseted bag in which the zipper is operated by a slider. The slider is configured so that the gussets, when folded, do not interfere with the operation of the slider. Therefore the disclosed embodiment employs a slider that does not have a separating finger. When the zipper is closed by the slider, the upper sections of the gussets are folded and captured between the interlocked zipper profiles. End stops are provided on the outside of the zipper parts to prevent the slider from sliding off the ends of the zipper. At the end of the package where the slider is parked when the zipper is fully open, the gusset will always be folded. Consequently, the latter end of the package mouth can never be opened widely because the gusseted side of the package in the area of the zipper cannot be expanded. However, this provides xe2x80x9clittle or no interference with expansion of the package gussets, especially towards the bottom of the packagexe2x80x9d.
There is a need for alternative designs of gusseted bags having slider-operated zippers in which portions of the folded gussets are not captured between the zipper profiles, thereby allowing smooth uniform sliding of the slider along its entire run.
The invention is directed to structures for side-gusseted bags or pouches having slider-operated zippers.
One aspect of the invention is a bag comprising: first and second walls, a first side gusset on one side of the bag interconnecting the first and second walls, and a second side gusset on an opposite side of the bag interconnecting the first and second walls; a flexible zipper comprising a first zipper part at least a major section of which is joined to the first wall and a second zipper part joined to the second wall, the first zipper part comprising a first profiled closure member and the second zipper part comprising a second profiled closure member that is engageable with the first profiled closure member to close the zipper; and a slider mounted to the zipper and configured to close portions of the zipper as the slider is moved in a first direction along the zipper and to open portions of the zipper as the slider is moved in a second direction along the zipper opposite to the first direction, wherein no portion of the first and second side gussets is captured between the first and second profiled closure members when the zipper is closed.
Another aspect of the invention is a bag comprising: first and second walls, a first side gusset on one side of the bag interconnecting the first and second walls, and a second side gusset on an opposite side of the bag interconnecting the first and second walls; a flexible zipper comprising a first zipper part at least a major section of which is joined to the first wall and a second zipper part joined to the second wall, the first zipper part comprising a first profiled closure member and the second zipper part comprising a second profiled closure member that is engageable with the first profiled closure member to close the zipper; and a slider mounted to the zipper and configured to close portions of the zipper as the slider is moved in a first direction along the zipper and to open portions of the zipper as the slider is moved in a second direction along the zipper opposite to the first direction, wherein a first end of the first zipper part is joined to a first end of the second zipper part, the first zipper part has a length greater than the width of an confronting section of the first wall and extends beyond the edges of the first wall on both sides thereof, and the second zipper part has a length greater than the width of an confronting section of the second wall and extends beyond the edges of the second wall on both sides thereof.
A further aspect of the invention is a gusseted bag comprising front and rear walls interconnected by a pair of side gussets and a slider-operated zipper, the zipper comprising first and second zipper parts that in turn comprise first and second profiled closure members respectively, wherein no part of the side gussets is captured between the first and second profiled closure members when the latter are interlocked.
Another aspect of the invention is a gusseted bag comprising front and rear walls interconnected by first and second side gussets and a zipper having a length greater than the width of the front wall. The zipper comprises first and second zipper parts joined at respective first ends near to the first side gusset and engageable but not joined at respective second ends near to the second side gusset. Portions of the first and second zipper parts other than the joined first ends are engageable to close the zipper and disengageable to open the zipper. The second side gusset is configurable to form a pouring spout when the zipper is open.
Yet another aspect of the invention is a device comprising first and second elongated zipper parts of equal length joined at both ends, the first and second zipper parts being engageable and disengageable along a major section disposed between the joined ends, one of the joined ends being joined only by peel seal material and the other of the joined ends being permanently sealed.
Other aspects of the invention are disclosed and claimed below.